Re: reject_unknown_client_hostname when nameserver is unreachable

[Wietse Venema]

Karel:
> Hello,
> 
> I am using following smtpd_client_restriction:
> 
>   reject_unknown_client_hostname
> 
> Now, both my nameservers were offline, and postfix could not resolve IP
> addresses and thus rejected all hosts:
> 
>   NOQUEUE: reject: RCPT from unknown[x.x.x.x]: 450 4.7.1 Client host
> rejected: cannot find your hostname, [x.x.x.x]

Note that this is a 450 status, because the name server did not reply.
A proper SMTP client will therefore try to deliver the email later.

        Wietse